State regulators on Wednesday issued a draft decision approving plans to expand natural gas service statewide over the next 10 years to 280,000 new customers by building 900 more miles of pipeline.

The plans by Yankee Gas, Connecticut Natural Gas, and Southern Connecticut Gas target customers who have gas available on their streets but have not yet connected as well as interested potential customers not close enough to existing gas lines to connect.

The Public Utilities Regulatory Authority said the effect on current customers’ rates “should be kept to a minimum,” but did not give details on average increases for residential and business customers.

Customers added after Jan. 1 would be charged a premium over current rates to offset expansion costs instead of an upfront payment. After 10 years, the surcharge would end and the customer would pay standard rates.

Chris Herb, president of Connecticut Energy Marketers Association, criticized the decision as “a tainted plan” that will increase energy costs rather than lower them.

Herb, whose group represents small oil dealers, said the companies and their shareholders should shoulder the cost.

Yankee Gas proposes to convert 10,000 non-heating customers to heating, add 41,296 new customers who can be connected now, and 31,125 customers too far from present pipelines by 2023.

Revenue earned through interruptible and off-system sales will be used to offset expansion costs for current customers rather than returned to customers as a bill credit. If that and the new customer surcharge aren’t enough to cover expansion costs, existing customers would be charged to make up the difference.

Gov. Dannel P. Malloy said that the move is “great news for Connecticut consumers” and “will mean lower monthly bills, a more competitive posture for our businesses, and new jobs and improved air quality.”

PURA asked for written comments by Nov. 12, with oral arguments scheduled for Nov. 14. It said it will issue a final ruling on Nov. 21.